There are known in the prior art protective helmets especially adapted for use by military personnel. Certain helmets of the prior art are intended to protect the head of the wearer against injury resulting from bumps and the like such as might be encountered by personnel in a tank. Ballistic helmets of the prior art are intended to protect the head of the wearer against injury resulting from missiles and the like. Many helmets of the prior art combine protection against injury resulting from bumps and the like with protection against injury from ballistic missiles. U.S. Pat. No. 3,786,519 discloses a headgear structure or helmet assembly which combines bump protection with ballistic protection.
Many military users of protective helmets must use sighting devices which require that the user's eye or eyes be brought into relatively close proximity to the sighting device. The construction of most protective helmets of the prior art is such that the wearer's eye cannot be brought into close proximity to a sighting device while the helmet is on the wearer's head. Thus, in order to effectively use the sighting device, the wearer must doff the helmet and sacrifice the protection afforded thereby.
Structurally, the helmet shown in U.S. Pat. No. 3,786,519 includes a flexible inner helmet and a rigid outer assembly. The inner assembly is made up of a fabric envelope which fits closely over the wearer's head. It has a plurality of pockets for receiving pads of bump-resistant impact-absorbing material. These pockets include one which extends across the forehead of the wearer and which receives an insert of bump-resistant impact-absorbing material. This inner flexible helmet affords the wearer's head protection against injury from bumps and the like. The rigid outer shell of the helmet assembly shown in the patent discussed above, is formed as a unitary body covering the forehead crown and nape portions of the inner helmet. It affords the wearer ballistic protection while the inner helmet affords protection against bumps.
U.S. Pat. No. 4,023,209 represents an attempt to adapt the helmet structure shown in the '519 patent to the needs of a sighter or one who must use a sighting device such as a gunsight. In the construction shown in the '209 patent the forehead pocket of the inner helmet carries an insert which gives the wearer ballistic protection in the forehead region. The rigid outer shell includes a rear portion covering the nape and crown portions of the inner helmet and so constructed as to afford ballistic protection in these regions in addition to the bump protection afforded by that portion of the inner helmet which is covered by the rear portion of the outer shell. The outer shell includes a separate forehead piece which is detachably secured over the forehead portion of the inner helmet by VELCRO fasteners or the like. This removable piece serves only to distribute forces applied thereto over the ballistic pad carried by the forehead pocket of the inner helmet.
While the construction of the helmet shown in the '209 patent represents an attempt to solve the problem of fully protecting a sighter's head against injury, it is not entirely satisfactory. First, owing to the presence of the frontal ballistic pad in the inner helmet structure, a sighter cannot bring his eye as close as is desirable to the sighting device even with the forehead portion of the outer shell removed. Secondly, owing to the fact that ballistic material has been substituted for the bump resistant material in the frontal portion of the inner helmet, the wearer is not afforded the degree of protection against bumps which is desirable. Thirdly, the removable forehead portion of the outer shell is not accurately located on the inner shell even when in place and may easily become dislodged therefrom.